Just a quick update on this - following on from Zhekas suggestion I did the following:

Set BarPeriod to 5minutes, then used TimeFrame = frameSync(12); for use in creating various indicators that represented a 60minute period (I found this more stable than the 30 minute periods I was using before). I could then also set TimeFrame = 1; so that I could use a faster price and frequency to check if this crossed my MA every 5 minutes rather than every 60.

Seems to be doing what I expect, however, I will continue to analyse my exits as not totally happy there yet.